Preheat the oven to 350°F (175°C) and prepare a baking pan.
In a mixing bowl, combine the melted butter and granulated sugar, mixing until well combined.
Add the eggs one at a time, beating well after each addition. Then stir in the vanilla extract.
In a separate bowl, whisk together the dry ingredients: flour, cocoa powder, baking powder, and salt.
Gradually combine the dry ingredients with the wet mixture, stirring until just incorporated.
Pour the batter into the prepared brownie pan and spread it evenly.
Bake in the preheated oven for about 25-30 minutes, or until a toothpick comes out with a few moist crumbs attached.
Allow the brownies to cool completely in the pan before cutting into bite-sized pieces.
Melt the green candy melts or white chocolate according to package instructions, then use it to attach candy eyes to each brownie bite.